They are not difference at all, people who are killers are just ordinary people thats the circumstances, situations and turnout of events in their life have shaped the way they ended up becoming, a lady may be beautiful and smart and sharp but deep down she may have a vengeful attitude and a vengeful attitude can in fact warrant murder , so therefore a man may look big and muscular but deep down have a softness in his heart I don't think people are born with the tendencies to become killers although they may possess violence in their gene but the truth is that only circumstances and situations in life that can bring out or suppress these gene inside of them.
Sometimes people kill other people mistakenly, it could be a sudden burst of rage let's take another example someone who becomes an armed robber in order to provide for his family these two people that are mentioned here are killers but the truth is that they are human and they are capable of love and showing love too but the truth is that some things have changed in their life that makes them embrace the darkness in them, believe me everybody has a destructive gene in them that will make them prospective killers but sometimes this game never suffices this is because it may be that the tunnel to event in their life was very positive so if you must know as much as we see people everyday who are smiling and that caring they have a killing tendency inside of them that will only suffice when there are some desperate turnout of events in their lives.
So there are no difference, killers are people and people are killers you can't take away people from killers and you can't take away killers from people. Sometimes you notice vengefulness and wickedness from some people which makes them very destructive but believe me they are not different from you the only difference is that the darkness in them has been unleashed why the darkness in you is being suppressed . Killers have their humanity deep buried inside of them that is why sometimes people who are criminals serves jail term and come out to become better people so there is definitely no difference as a result of the reason I gave you
Anyone can be a killer.
It's just a matter of circumstance.
What is a fundamental difference between taking the life of one animal over another animal other than Social programming?
Billions of People eat meat.
But it's wrong to eat another human...
It's not really. It's just that as Social animals we frown upon the decay of the Social structure.
They have the urge to kill and feel that adrenaline kick.